a remembrance of [Israel through] the shofar blast: [On this Rosh Hashanah day,] a remembrance [before God of the Jewish people is evoked through the sounds of the shofar. And in order to enhance this remembrance, our Rabbis instituted the recitation] of Scriptural verses dealing with remembrance and Scriptural verses dealing with the blowing of the shofar (R.H . 32a), through which the remembrance of the binding of Isaac is recalled for them, [whereby Isaac was willing to be sacrificed as a burnt-offering according to God’s words (see Gen. 22:119), and] in whose stead a ram was offered up [whereby the shofar alludes to that ram’s horns, by which it was caught in a tree, thus making its appearance as Isaac’s replacement (see Gen. 22:13)]. — [Sifthei Chachamim, Gur Aryeh; R.H. 16a]

But: Heb. אַךְ. Wherever the word אַךְ, “but,” or רַק, “only,” appear in the Torah, they denote an exclusion. [Thus,] Yom Kippur atones for those who repent, “but” it does not atone for those who do not repent. — [Shev. 13a]

I will destroy: כָּרֵת (“excision” or “cutting off”) is stated [as a punishment] in many places [in Scripture] and I do not know what that means, when God says [explicitly] “I will destroy,” [coinciding with וְנִכְרְתָה in the preceding verse,] this teaches us כָּרֵת means only “destruction” [i.e., premature death, and not that the body is to be cut up or that the person is to be exiled]. — [See Be’er Basadeh on this verse and on 22:3 above; Torath Kohanim 23:180]

You shall not perform any work: [But has this not already been stated in verses 28 and 30 above? Yes, nevertheless this prohibition is repeated several times here, so that one who disobeys] transgresses many negative commandments, or to warn against work at night [that it is forbidden just] as [performing] work during the day [of the tenth of Tishri]. - [Yoma 81a; see Mizrachi and Divrei David]